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排序方式: 共有83条查询结果,搜索用时 234 毫秒
1.
In the presence of trialkylamine and formic acid RuCl2(PPh3)3 selectively reduces aldehydes to the corresponding alcohols at room temperature. Other reducible groups are unaffected. 相似文献
2.
Kam Yee Yoon Wen Siang Tan Beng Ti Tey Khai Wooi Lee Kok Lian Ho 《Electrophoresis》2013,34(2):244-253
Hepatitis B core antigen (HBcAg) expressed in Escherichia coli is able to self‐assemble into large and small capsids comprising 240 (triangulation number T = 4) and 180 (triangulation number T = 3) subunits, respectively. Conventionally, sucrose density gradient ultracentrifugation and SEC have been used to separate these capsids. However, good separation of the large and small particles with these methods is never achieved. In the present study, we employed a simple, fast, and cost‐effective method to separate the T = 3 and T = 4 HBcAg capsids by using native agarose gel electrophoresis followed by an electroelution method (NAGE‐EE). This is a direct, fast, and economic method for isolating the large and small HBcAg particles homogenously based on the hydrodynamic radius of the spherical particles. Dynamic light scattering analysis demonstrated that the T = 3 and T = 4 HBcAg capsids prepared using the NAGE‐EE method are monodisperse with polydispersity values of ~15% and ~13%, respectively. ELISA proved that the antigenicity of the capsids was not affected in the purification process. Overall, NAGE‐EE produced T = 3 and T = 4 capsids with a purity above 90%, and the recovery was 34% and 50%, respectively (total recovery of HBcAg is ~84%), and the operation time is 15 and 4 times lesser than that of the sucrose density gradient ultracentrifugation and SEC, respectively. 相似文献
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5.
Comparing several population means: a parametric bootstrap method, and its comparison with usual ANOVA F test as well as ANOM 总被引:3,自引:0,他引:3
This paper deals with testing the equality of several homoscedastic normal population means. We introduce a newly developed
computational approach test (CAT), which is essentially a parametric bootstrap method, and discuss its merits and demerits.
In the process of studying the CAT’s usefulness, we compare it with the traditional one-way ANOVA’s F test as well as the analysis of means (ANOM) method. Further, the model robustness of the above three methods have been studied
under the ‘t-model’. The motivation behind the proposed CAT is to provide the applied researchers a statistical tool to carry out a comparison
of several population means, in a parametric setup, without worrying about the sampling distribution of the inherent test
statistic. The CAT can be used to test the equality of several means when the populations are assumed to be heteroscedastic
t-distributions. 相似文献
6.
Duong Minh Duc Tran Vinh Hung Nguyen Tien Khai 《Proceedings of the American Mathematical Society》2007,135(3):921-927
Using elementary differential calculus we get a version of the Morse-Palais lemma. Since we do not use powerful tools in functional analysis such as the implicit theorem or flows and deformations in Banach spaces, our result does not require the -smoothness of functions nor the completeness of spaces. Therefore it is stronger than the classical one but its proof is very simple.
7.
V. Z. Stankevich B. M. Stasyuk O. M. Khai 《Journal of Applied Mechanics and Technical Physics》2005,46(1):124-128
The three-dimensional dynamic problem of coplanar circular cracks in an elastic half-space with a clamped boundary condition is considered. The crack faces are subjected to harmonic loads. The problem is reduced to a system of two-dimensional boundary integral equations of the type of the Helmholtz potential for unknown discontinuities in the displacements of the opposite faces of the cracks. The stress intensity factors at the crack contours are obtained and discussed.Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 46, No. 1, pp. 153–159, January–February, 2005 相似文献
8.
The one-dimensional process of the heating of a saturated porous medium by a volume heat source as a result of the absorption of the energy of a high-frequency (frequency R~ 101–103 MHz) electromagnetic wave is investigated. It is assumed that in the initial state the saturating (second) component is in the high-viscosity liquid or solid state. Under the action of the heat it is heated, melts, expands, becomes less viscous and under the pressure head created may flow relative to the stationary rock skeleton (first component). On the basis of the mathematical model proposed the basic laws of the process are analyzed and numerically investigated in the case of one-dimensional axisymmetric motion. It is shown that under actual conditions the dimensions of the thermal influence zone may be very considerable. Thus, by varying certain external factors it is possible to modify the dynamics of the process and the distributions of the temperature, pressure and phase velocity fields.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 4, pp. 115–124, July–August, 1991. 相似文献
9.
I. S. Ignat’ev M. G. Voronkov T. A. Kochina G. S. Samokhin V. V. Belyaeva S. Ya. Khai’kin 《Journal of Structural Chemistry》2014,55(3):431-437
IR spectra of 1-germatranol, 1,1-quasi-germatrandiole, 1,1,1-hypogermatrantriole with a general formula (HO)4?n Ge(OCH2CH2) n NR3?n (n = 1–3) are obtained. At the B3LYP/aug-cc-pVDZ density functional level the equilibrium structures and vibrational spectra of these compounds along with their hydrogen-bonded dimers are calculated. Based on the calculations the band assignment is performed in the IR spectra of 1-germatranol, 1,1-quasi-germatrandiole, and 1,1,1-hypogermatrantriole. The existence of dimers is manifested in the IR spectra as the absence of bands in the frequency ranges characteristic of the bending vibrations of Ge-OH groups and the presence of bands in the vibrational range of hydrogen-bonded germatranyl groups. 相似文献
10.
Khai Xuan Pham Rie Tanabe Yoshiro Ito 《Applied Physics A: Materials Science & Processing》2013,112(2):485-493
Laser-induced periodic surface structures (LIPSSs) were observed on the sidewalls of 300-μm-diameter holes trepanned on cemented tungsten carbide using femtosecond laser pulses at a wavelength of 800 nm. For a circularly polarized beam, LIPSSs were formed at a period of 300 nm and oriented perpendicularly to the plane of incidence on the sidewalls. For a linearly polarized beam, LIPSS formation was dependent on the relative angle α between the polarization direction and the plane of incidence. For relative angles α from 0° to 70° and from 110° to 180°, LIPSS spacing was 300 nm. However, there were two types of LIPSSs coexisting from 70° to 110°. One had a spacing of 120 nm and the other had a spacing that varied from 500 to 760 nm. It was found that the orientation angle of LIPSSs measured between the LIPSS orientation and the plane of incidence had a nonlinear dependence on α. To understand this dependence, a model was proposed in which LIPSSs are assumed to align perpendicularly to the direction of the absorbed electric field lying in the tangent plane of the sidewall of a drilled hole. The calculated results from this model showed good agreement with the experimental results. 相似文献